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Magnetic Ring Could Launch Satellites, Weapons
MattSparkes writes, "A new study funded by the US Air Force has suggested a cheaper method of sending satellites (possibly missile weapons) into orbit. A 2-km-wide ring of superconducting magnets would contain and propel a payload, accelerating it over a period of hours, before suddenly flinging the satellite into space at 23 times the speed of sound. The satellites would be engineered to withstand the g-forces encountered (2,000 g), and be cased in an aerodynamic shell. A two-year study has been commisioned and will begin within a few weeks at LaunchPoint Technologies in Goleta, California." New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet."
Am I the only one seeing the parallel?
I'm a fiscal conservative, it's a pity we don't have a political party anymore
Space burials (presumably of cremated remains). At $200 each (plus cremation) I am sure they could sell a few thousand of these per year. Now if they could only figure out a way to allow living people to withstand 2000g of acceleration, space tourism might actually be affordable.
I Am My Own Worst Enemy
We could fling refrigerators at North Korea! How's that missile testing going, Kim, did we mention we can launch frigidaire's into orbit? I'd prefer launching cows in homage to Monty Python and the Holy Grail, but at 2000g, that would probably equate to throwing hamburger.
"Don't you know you're going to shock the monkey?"- Peter Gabriel
Yes!
As for it being a target, fuck that. Full steam ahead.
If we're not driving payloads into space at Mach 23 within 10 years, the terrorists have already won. Or something.
If this ring is going to be "one of the most important targets on the planet", maybe they should build it as a series of concentric rings instead of a single ring. Perhaps havethe rings use alternating colors.
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"
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-James Baldwin
Suggestion for the first test: Enter it in next year's Punkin Chunkin' contest!
>> "What would the robut do? Frame someone!"
http://en.wikipedia.org/wiki/M712_Copperhead
Now you're aware...
The world is made by those who show up for the job.
First the FUD:
New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet.
What a moronic comment.
You have a STATIC launcher.
It can toss things into ballistic trajectories.
One at a time.
With a warm-up of TENS OF HOURS.
I don't know if New Scientist realized this, but we have launch technologies that are
a) less vulnerable
b) more accurate
c) mobile
and
d) a little quicker to fire than that.
On another note, and not that this will mollify the crowd that fears a weapon in every technology, but in regards to the difficulty of punching something through the atmosphere at Mach 23, I seem to recall SDI experiments where a high-power laser was used to heat a 'track' through the atmosphere (in that case, to fire a particle beam weapon down the track with less atmospheric attenuation ). Couldn't a similar idea significantly reduce the air resistance for this sort of a projectile?
-Styopa
Your lapse is forgivable, but only because the proliferation of terms like "Gauss gun", "rail gun", and "mass driver" in SF has overwhelmed their usage as technical terminology. But the point is, THIS IS NOT A RAIL GUN.
A rail gun is a parallel, non-touching pair of conductive rails, joined at the back-end by a partial circuit capable of generating an extremely high current flow (amps) of electicity in a very, very short time. A conductive projectile is injected into the gap between the rails (so that it touches both rails at once), which completes the circuit. As current flows from one rail to the other, through the projectile, it generates a powerful magnetic field. The Lorentz force causes the projectile to be pushed toward the far end of the rails--the magnitude of the force depends on the current flow.
Rail guns can achieve extremely high velocities, far higher than conventional explosive-charge guns. The velocity of a firearm projectile is limited by the velocity of the expanding explosive gasses that propel it out of the barrel; the gas velocity is in turn limited by the speed of sound in the gas medium, which has a physical upper limit for any type of explosive. Rail guns don't suffer from this limitation.
I have seen references to a 'Gauss gun' which consists of a series of solenoids stationed along a tube barrel, timed to trigger so that a ferrous metal projectile will be pulled faster and faster down the barrel by each of the solenoids in turn. I don't know how valid this terminology is, though.
"My pacemaker!"
"Flyin' in just a sweet place,
Never been known to fail..."
You mean, like Vandenberg, and Cape Kennedy, and...
Anywhere the capability exists to put a payload into orbit is a target.
That "most important target" bit was a simple piece of scaremongering.
668: Neighbour of the Beast
What about using this thing to shoot water/food/structural materials into space? That is where the savings really come into play. If there is to be a moon base, all the water has to be shipped up there. People need lots of water, so cutting the cost per kilogram to 1% of current levels is a very big deal.
This post climbed Mt. Washington.
Except that the proposed design accelerates the payload around in a circle -- using magnets arranged inside a torus -- not a long straight runway. I doubt a linear runway would be practical; it would just be too long. The advantage of a torus is you can keep using the same magnets to accelerate the payload, over and over, until you've reached sufficient speed to let it fly.
Unless the circle was ridiculously large (probably the size of a continent or better), you're not going to be able to get up to escape velocity before you'd (as a human being) would be crushed by the effects of the centripetal acceleration.
I'm not going to do the math right now, but I'm pretty confident that of the 6,000 Gs they're quoting, most of them are in the radial direction and not in the tangential, so that even if you brought the payload up to speed slowly, you'd still be crushed. It would be just like being in a centrifuge.
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The reason that most meteors don't hit the ground is because they are so small. The one that do hit the ground and are found right away often have FROST on them since they were so cold in space. As for exploding into a million pieces, meteors aren't designed for reentry.
Any compentent aeroshell engineer could design a case that would protect the payload (such as a capsule covered with the stuff they use for ablatively cooling rocket nozzles). The big concern usually with burning through airframes isn't that we don't have materials that can withstand the heat and friction; it is that those materials typically aren't very light-weight or are too expensive.
Besides, once the track is set up, it should be easy to try out new aeroshell designs! One of the stumbling blocks right now is trying to accellerate a test article to high enough speeds. Very often, they stick a test article on a sounding rocket that sends back data during re-entry.
And yes, IAARS.
science is a religion
Am I crazy, or did they get the math wrong in the article?
The acceleration equation for circular motion is: a = v^2 / r
We are given:
Velocity: 10 kilometers/s
Width of ring = 2 kilometers, so radius = 1 kilometer
So:
v = 10,000 m/s
r = 1,000 m
a = (10,000 m/s * 10,000 m/s) / (1,000 meters) = 100,000 m/s^2
The acceleration due to gravity is about 10 m/s^2
This gives: (100,000 m/s^2) / (10 m/s^2) = 10,000 g
So it seems that their 2,000 g is way off. Even if we use 2 km for the radius it is still 5,000 g.
Reading code is like reading the dictionary - you have to read half of it before you can go back and understand it.
A few reasons... the ring is kilometers long. Angling it at 30 degrees would force you to build it deep into the ground, high into the air, or both. But more importantly you'd only have one launch trajectory. By having one ring and a mobile launch tunnel you have 360 degrees to choose from (ideally). The ability to change launch direction is probably more important than the complications it adds to the launch physics.
Developers: We can use your help.
The long-term expensive part about space is not sending equipment up. It is the costs of fuel, water, air, and food i.e. consumables. Fuel and Water can all withstand the high Gs. If this works, the first thing that would make sense is to send all of these up. At that point, you can make the ring pay for a large part of its costs. From there, sats. can be developed that can withstand those forces.
The down fall is that the privatization world will probably be a bit upset about this.
I prefer the "u" in honour as it seems to be missing these days.
Cute, but you gotta be kidding. I work with a 3T research MRI magnetic. Both the machine and the facility are heavily shielded, and the field drop-off is very steep. While the isocenter of the bore is at 3 Tesla (30,000 Gauss), the 5 Gauss line is only a few meters (about 5 in the axial direction, 3 in the radial direction) from the isocenter. By comparison, a kitchen magnet is maybe 100-250 Gauss.
Federal Express, when it absolutely, positively has to be there at 23 times the speed of sound *
* Disclaimer: 23 X speed of sound service available between limited destinations. May be subject to 2000g so please wrap delicate items approprately.
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This ring could fling mass up to a skyhook to recharge its orbit. Imagine a LEO skyhook that catches dozens of dead weight shots from this gun and uses that momentum to promote its orbit to a highly eccentric one. Then the satellite can exchange this orbit potential with a target at its low altitude point through a tether or skyhook style method. The target could be a large satellite in LEO or even a suborbital payload. Once the potential is transfered the target can have its orbit promoted to GEO or other significant altitude.
This method saves a lot of reaction mass in a heavy lifter because you can aim for a high alitutde but a suborbital trajectory. IE it's easier to shoot straight up than curve towards an orbital path at sufficient speed. For instance the X prize is all about sub-orbital. LEO is much harder and GEO is even harder still.